The present invention relates to an endoscope using a multi-lumen tube in an insertion section.
An endoscope of this type is disclosed in U.S. Pat. No. 4,576,145. An insertion section of this endoscope includes an elongated multi-lumen tube, formed of a flexible resin. The multi-lumen tube contains a plurality of conduits, each having a predetermined inside diameter and extending in the axial direction of the tube. Some of the conduits are used as an image guide duct or light guide duct, in which optical fibers, lenses, etc., are inserted. The other conduits serve as an air/water channel duct for air or water supply, or an instrument channel duct in which a medical instrument is inserted.
As stated in Japanese Utility Model Disclosure No. 55-171001, however, the multi-lumen tube is molded by extrusion. After it is molded therefore, the tube may possibly contract, thereby reducing the diameters of the conduits or changing their sectional configurations. Thus, it sometimes is very difficult to insert the optical fibers and lenses into the conduits, after the multi-lumen tube is formed on the conduits.
Moreover, pipes, extending from an operating section of the endoscope, are inserted individually into the instrument and air/water channel ducts, so that the conduits and their corresponding pipes are connected. The respective sectional configurations of the pipes are usually uniform, while those of the conduits are different. Accordingly, the pipes cannot be inserted properly into the conduits, thus entailing defective connection.